Coal sludge

Coal sludge, also known as slurry, is the liquid coal waste produced by mining activities. After mining, coal is crushed and washed to remove the surrounding soil and rock. The washing process generates huge amounts of liquid waste, and the mining process itself produces millions of tons of solid waste. Coal companies usually dispose of this waste by constructing dams from the solid mining refuse to store the liquid waste. These impoundments are usually located in valleys near their coal processing plants.

Coal sludge is filled with toxins. Each year coal preparation creates waste water containing an estimated 13 tons of mercury, 3236 tons of arsenic, 189 tons of beryllium, 251 tons of cadmium, and 2754 tons of nickel, and 1098 tons of selenium.

The term coal sludge is also sometimes used to refer to coal waste as a whole.

2010 WVU report on coal slurry
In August 2010, a 418-page report released by researchers at West Virginia University was "inconclusive" on the health effects of injecting coal slurry into the ground, citing data gaps. WVU's report notes, however, that federal documents and other literature provide reason to believe injection "does not always work as intended" and can contaminate ground and surface water. For decades, coal companies in Appalachia have injected slurry into worked-out underground mines as a cheap alternative to building dams or filtration and drying systems. The report says 70 million to 90 million gallons of slurry is created nationwide each year. The industry defends the practice as safe. But critics say the earth continues to shift and crack long after mining has ended, whether through natural settling or activity such as nearby blasting, and that lets slurry migrate, sometimes into drinking water supplies. Hundreds of southern West Virginia residents are now suing coal companies, claiming slurry poisoned their wells and made them sick. Legislators have waited 3 1/2 years and spent more than $220,000 to learn whether coal slurry pumped into abandoned underground mines is dangerous to people who live nearby. But WVU researchers say their report is inconclusive.

On August 9, 2010, a legislative subcommittee is set to hear a presentation on the report in Charleston, and will hold the third of a series of hearings on slurry. Concerned residents plan to argue a temporary moratorium on new injection sites - imposed in WV in 2009 - should be made permanent while legislators figure out how to provide public health officials more answers. It's unclear what the health department might recommend to develop more data, and how they may act on the coal slurry injection moratorium.

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